The LES stays closed except during swallowing, when it allows food to pass from the esophagus into the stomach. When the LES is closed, it prevents the backflow (reflux) of stomach acid into the esophagus. If the LES does not close tightly enough, stomach acid backs up into the esophagus, causing heartburn. A weak lower esophageal sphincter is a major cause of gastroesophageal reflux disease (GERD).
|Primary Medical Reviewer||Adam Husney, MD - Family Medicine|
|Specialist Medical Reviewer||Peter J. Kahrilas, MD - Gastroenterology|
|Last Revised||March 6, 2012|
WebMD Medical Reference from Healthwise